Functionality and Architecture of RFID Handheld Reader

Understanding RFID handheld reader

Handheld reader is an important component of the RFID system. Despite its name, the reader's function is not just to read tag information. The reader also includes many auxiliary functions such as host communication, IO control, etc. The reader powers the tag through the electromagnetic waves radiated by the reader's antenna, sends synchronization clock and Gen2 air interface commands, and receives data returned by the tag. The communication between the reader and the tag is half-duplex, which means that the reader cannot receive data from the tag when sending data to the tag.

However, since the tag is a passive device and cannot store energy, the reader needs to be powered in real-time. When the tag sends data to the RFID handheld reader, the reader must send a carrier to provide energy to the tag. This is the unique half-duplex communication method of the ultra-high frequency RFID system. This special half-duplex communication method brings many technical challenges to the reader, such as self-interference problems and linearity problems of the receiving link.

Understanding the function and structure of RFID handheld reader

Although the RFID handheld reader is always in host mode during communication with the tag, the reader actually works with the tag. When the tag's function is upgraded, the reader needs matching operating commands with that function to achieve new applications. When the sensitivity of the tag is improved, the receiver sensitivity of the reader needs to double to ensure stable communication, such as when the tag sensitivity is increased by 3DB. When the tag's reverse scattering ability remains unchanged, the reader needs to increase the sensitivity by 6db to ensure that the forward link budget is equal. Of course, there are many reader problems waiting for us to solve, such as the need for one reader to inventory thousands of tags in many applications. At this time, the system has very high requirements for the reader's sensitivity, anti-interference, and multi-tag algorithm, and the reader is constantly improving and progressing for different application scenarios.

The other end of the RFID handheld reader is connected to a computer, which can be understood as connecting to a data terminal or processor terminal. Only by connecting the reader to the system can we control the operation commands and transmit data, thereby obtaining tag data information and forming data collection nodes in the Internet of Things. The reader is not only a collection point for tags but also a collection node for sensors or a control node for sensors. With the advancement of technology and the development of the industry, the function of the RFID handheld reader will become larger and its position in the Internet of Things will become more important.